Image analysis is necessary for full data extraction from new autoradiographic techniques available to trace biological events and to analyze structure/function relationships in brain; it is also necessary for full data extraction in studies which evaluate morphological features of cells, in their normal and/or abnormal states; it is especially accurate and time efficient for standard analysis techniques, e.g. microdensitometry of gels with high background complications. A major advance of the image analysis system commercially available from Cambridge Instruments, the Quantimet 900, is that it is relatively simple to use, and it performs multiple functions such as microdensitometry and three dimensional reconstructions. This user group has special needs for microdensitometry of variable-sized brain areas with simultaneous area measurements, and three dimensional reconstructions; image averaging to reduce noise or to detect change; image enhancement; area and shape analysis; high resolution. The projects and questions being asked are diverse; from neuroanatomical-functional questions in normal and diseased brain, and in "simple" invertebrate systems, to cell motility questions and basic genetics. There are six major user groups; two of the groups involve several investigators. The image analysis system requested will not only help current projects of the major user group and other researchers at this institution, but it will also be a powerful addition for future studies which would be impossible without it.